Used as an exta security option, mostly used in all types of security and safety procedures. Mostly, it is used to check if someone is out for trouble, and used by the bouncer at a club.
A person who has betrayed you or people you love, therefore making them a fuckface. Fuckfaces come in all different shapes and sized. In some cases, it involves insecure thin guys who break girls' hearts and blame it on their insecurity, or a horny football prayer who can't stop fucking people over.